共查询到20条相似文献,搜索用时 15 毫秒
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双金属薄壁管冲击液压胀形技术是在液压胀形与冲压成形基础上发展起来的一种复合成形技术。为了获取更好的成形质量,在液压预成形与冲击液压成形相结合的基础上,通过改变液压预成形的加载路径实现双金属薄壁管成形。介绍双金属薄壁管冲击液压成形原理及内管轴向补料方案;利用Dynaform有限元分析内管轴向补料距离对双金属薄壁管壁厚分布的影响,获得轴向补料距离对双金属薄壁管成形规律;同时,分析内管轴向补料距离对管材中截面的对角线长度变化影响规律,从而获得内管轴向补料距离对双金属薄壁管填充性的影响。通过液压预成形阶段加载路径的研究,探明了轴向补料对双金属薄壁管成形规律的影响,为冲击液压载荷作用下的双金属薄壁管成形提供理论与应用支撑。 相似文献
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介绍了半锥角<1°的LF6合金锥筒旋压成形过程。实验表明,LF6合金小锥度铝筒零件,用筒形锻坯在直筒芯模上变薄旋压,再用小锥度芯模普旋收锥成形是可行的。文章分别对确定初始锻坯尺寸、室温下强旋变薄铝筒、加热普旋成锥形零件以及实验中出现的问题进行了说明。实验为LF6合金小角度无缝锥筒塑性加工成形提供了参考。 相似文献
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文章将渐进成形的思想融入到传统的管件电磁胀形工艺中,提出管件电磁渐进成形的新工艺,即采用小尺寸线圈,通过移动多次成形的方式成形长管件。提出了适合于管件电磁渐进胀形工艺的顺序耦合数值模拟方法,并与一次放电、两次放电、三次放电的实验结果进行对比,模拟结果与3组实验数据均吻合。采用数值模拟的方法,进一步研究重叠率和成形顺序对管件变形均匀性的影响,研究结果表明,重叠率为50%、成形顺序为b→c→a时,可获得最佳的成形均匀性。电磁渐进成形技术应用于管件胀形工艺中具有可行性,对实际生产具有指导意义。 相似文献
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为解决金属双层管液压胀形过程中设备成本较高、成形效率较低、操作工艺较复杂等问题,提出了一种基于冲压成形和液压胀形技术的复合成形方法——冲击液压胀形。首先介绍了双层管冲击液压胀形的成形原理;然后,从成型部分、轴向进给部分、控制部分和辅助部分等4个方面介绍了冲击液压胀形装置;同时分析了双层管胀形过程中的受力状态;最后采用弹塑性理论,对双层管内管和外管的应力应变关系进行了讨论,并根据双层管变形协调条件,获得了胀形内压力pi的判定依据。冲击液压胀形技术将为双层管成形技术的研究提供新的科学依据和技术支撑。 相似文献
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Qingqing Zhang Ding Tang Dayong Li Yinghong Peng 《Journal of Materials Processing Technology》2010,210(14):1876-1884
Microchannel aluminum flat tubes have attracted more and more attention in recent years, especially in ACR (air conditioning and refrigeration) industry. Rotary-draw bending is a versatile and precise method in forming of tubes. Compared with traditional out-of-plane bending method, in-plane bending can cause different forming defects. During the process, wall thinning, sectional distortion, wrinkling, and channel shape degradation are the main defects that affect tube quality in industrial applications. In this paper, an experimental apparatus for flat tube in-plane bending is manufactured, and experiments are performed to examine the forming quality of tubes. Considering the characteristics of the bending process, based on the LS-DYNA software environment, a 3D elastic–plastic finite element model is established and validated by experiment. Using the validated FE model, the forming quality of microchannel flat tube bending process is evaluated quantitively. Furthermore, the influence mechanism of process parameters, such as bending radius, tool–tube clearance, and channel diameter, has been revealed. The results indicate that the degradation of the tube channels is relatively small under common process conditions; bending radius is the main factor which influences the forming quality of the flat tube; the tool–tube clearance mainly affects the wrinkling of the flat tubes; channel diameter has little effect on the formability of tube. 相似文献
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Heon Young Kim Hee Taek Lim Hyung Jong Kim Dong Jae Lee 《Metals and Materials International》2007,13(2):87-92
The effects of 2D and 3D prebending on the forming limit in the tube hydroforming process of an automotive rear subframe are
evaluated and compared through finite element analyses and experimental tryouts. The influence of the strain path corresponding
to each prebending method is discussed in terms of a forming limit diagram (FLD) and a forming limit stress diagram (FLSD).
An incremental strain-to-stress transformation scheme to plot the FLSD from the FLD along an arbitrary strain path is proposed.
A tube hydroformability testing system designed and manufactured to provide an arbitrary combination of internal pressure
and axial feed is introduced. A forming limit diagram of the A6063 aluminum tube material is obtained from free bulging, T-shape
forming and cross-shape forming tests using this system. 相似文献
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Material properties have powerful impact on the tube hydroforming (THF) process and the quality of the deformed tube, so it is important to select proper materials and evaluate the material formability prior to conducting the process. A simplified and applied tooling, which has no use for any external hydraulic pressure source but internal one, was designed for charactering the material formability in THF. A pressurized-fluid supplier is automatically established to provide the internal pressure and axial load synchronously required for THF, and the ratio of the two loads is achieved by proper design of the supplier. As a stand-alone hydraulic bulging fixture, the tooling can be worked on a conventional press, even on a single action press. Free bulge forming (FBF), bulge forming with axial loading (BFAL), free and restrained bulge forming (free and fixed ends) can be fulfilled by the tooling, and furthermore, bulge forming with proportional loading to some extend can be realized. Comparative bulge forming experiments under various forming conditions were carried out with the tooling to validate this project and the results suggest that restrained conditions on the tube ends highly affect the FBF, while the ratio of the two loads dominates the BFAL. 相似文献
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管件磁脉冲校形是指利用电磁成形工艺使管件在磁脉冲力的作用下高速撞击模壁并贴模的一种先进校形工艺。目前。电磁成形工艺中应用较多的是管件电磁胀形、缩颈以及平板成形,而管件校形工艺及理论研究很少。本文提出了一种基于ANSYS重启动分析的电磁一结构强耦合模型。模型考虑了管件变形对磁场计算的影响,能够准确的模拟电磁成形过程,并有效的避免了空气网格畸变对结构变形的影响。分析了电磁校形过程中管坯不同变形状态下系统的磁场力大小及分布。讨论了管件中最大磁场力的发生时刻,给出了模具中的涡流及磁场力的分布。 相似文献
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我国直缝焊管成型技术的进展 总被引:1,自引:0,他引:1
介绍了我国目前自产及进口的主要直缝焊管成型机组类型和各种典型成型法以及直缝焊管成型技术的发展。指出在消化吸收引进技术设备的基础上,国内已具备设计、制造先进直缝焊管机组的能力,但仍需要进一步开发成型技术,促进焊管行业的发展。 相似文献
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文章对LF2M-JG6×1挤压式无扩口导管材料性能和端头成形工艺进行了工艺试验研究,统计分析了试验数据,揭示了挤压深度与管材壁厚、挤压压力的关系,确定了导管端头成形工艺参数,解决了LF2M-JG6×1挤压式无扩口导管端头成形问题。 相似文献
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建立了不同过渡区参数的TRB(Tailor-Rolled Blank)管液压胀形有限元模型,提出了一种离散不规则过渡区的新方法,研究了TRB管过渡曲线、过渡区长度和厚度差对胀形性能的影响规律。针对TRB管液压胀形,进行了正交设计,以数值模拟结果为基础,建立了BP神经网络预测模型,并将预测结果与数值模拟结果进行对比分析,验证了预测结果的精度。结果表明:各参数对胀形性能影响的区域不同,但都对最大成形高度影响显著,极差最大达6.47 mm,最小为2.88 mm;凹弧型过渡曲线的成形性能最差,最大的成形高度差为2.88 mm;增大过渡区长度有利于胀形,随厚度差增加,成形性能快速下降,其中厚侧成形高度差值达8.22 mm。单组预测值在误差范围内,预测模型能用于预测其他过渡区参数组合的TRB管胀形。 相似文献